This invention relates generally to window and similar panel assemblies for installation in openings in the walls of buildings, and more specifically to an improved watertight windowsill construction suitable for use with fixed sash windows or the like having frame means made from extrusions of metal or rigid plastic material.
A fixed sash window is usually mounted in place by having its sill placed on a window base on a foundation of a building. The window base, which may be of wood, metal, lightweight concrete or like material, has holes formed vertically therethrough for receiving the anchor bolts that have been embedded in, and erected on, the building foundation. Nuts are tightened on the threaded ends of the anchor bolts protruding from the holes in the window base, in order to secure the window base to the foundation. The sill, which usually is an extrusion of metal (e.g. aluminum or its alloys) or rigid plastics (e.g. polyvinyl chloride), is screwed or otherwise fastened to the window base. Following the installation of the sill on the widow base, the spaces between the foundation and the bottom of the sill are caulked by filling in a wet type sealing compound by way of waterproofing.
The sill of a fixed sash window has an upstanding exterior flange which is held against the bottom periphery of a panel or pane of glass or like material via a fluidtight sealing strip. As rainwater will nevertheless intrude through the gap between the sealing strip and the window panel, the sill has formed in its bottom a series of drain holes along its exterior edge for draining the incoming water. U.S. Pat. No. 4,464,874 discloses such a windowsill having a series of drain holes.
As heretofore constructed, however, the windowsill has had no means for shielding the drain holes against the backflow of rainwater up through the holes toward the interior of the window. The rain that has struck the window panel will flow down the same and, futher running down the exterior flange of the sill, may reach the underside of the sill. If then the wind is strong, the rainwater has been easy to be blown up through the drain holes into the inside of the sill.
The drain holes in the sill have given rise to another problem in watertightly caulking the space that is created between the foundation and the bottom of the sill by the interposition of the window base therebetween and which extends along the row of drain holes. Having so far been exposed directly to the space to be caulked, the drain holes have been prone to be clogged up with the waterproofing compound. The caulking operation itself has tended to be very troublesome and time consuming since care has had to be taken so as not to block the drain holes.